Hi Kou, > What does "only one version of the library" mean here? Only > shared version or only static version? If we use > -DARROW_BUILD_SHARED=ON and -DARROW_BUILD_STATIC=ON, we can > build both of shared version and static version in the same > build process. Am I missing something?
That was a mistake on my part. What I meant was that, for "executable" targets, only one version can be linked: [1] https://github.com/apache/arrow/blob/acbad2942be80e9a76b888f99fe3b9ebdc4f2941/cpp/examples/arrow/CMakeLists.txt#L144-L148 [2] https://github.com/apache/arrow/blob/acbad2942be80e9a76b888f99fe3b9ebdc4f2941/cpp/examples/parquet/CMakeLists.txt#L51-L56 [3] https://github.com/apache/arrow/blob/acbad2942be80e9a76b888f99fe3b9ebdc4f2941/cpp/tools/parquet/CMakeLists.txt#L29-L33 Should we set an alias target in one place for such usages, for example: if(ARROW_BUILD_SHARED) add_library(parquet_lib ALIAS parquet_shared) else() add_library(parquet_lib ALIAS parquet_static) endif() , or just leave it be until there are more occurrences? Thanks, Eddie Sutou Kouhei <k...@clear-code.com> 於 2025年6月3日 週二 下午4:44寫道： > Hi, > > > However, with the current implementation, only one version of the library > > actually exists within a single build process. > > What does "only one version of the library" mean here? Only > shared version or only static version? If we use > -DARROW_BUILD_SHARED=ON and -DARROW_BUILD_STATIC=ON, we can > build both of shared version and static version in the same > build process. Am I missing something? > > > Thanks, > -- > kou > > In <cahgae5exol+9ohtujp+-n3vpssrgeajbxn1do0dlegbqsz6...@mail.gmail.com> > "Re: [C++] Static/Shared Linkage in CMakeLists.txt" on Tue, 3 Jun 2025 > 16:37:42 +0800, > Eddie Chang <kalcifer7...@gmail.com> wrote: > > > Hi Kou, > > > > Building both shared and static versions of the library simultaneously is > > certainly possible. My current focus is on the fact that we have multiple > > build targets linking against the same library, and each time we do so, > we > > repeat the same if-else logic to decide which version to link. > > > > However, with the current implementation, only one version of the library > > actually exists within a single build process. So we only need to > determine > > whether to build the static or shared version once―when building the > > library itself―instead of repeating the same check every time a build > > target links against the same library. > > > > If you'd like to support both versions, I suppose you already need to > build > > twice (with different build options) with the current implementation? > > Thanks, > > Eddie > > > > Sutou Kouhei <k...@clear-code.com> 於 2025年6月3日 週二 下午3:10寫道： > > > >> Hi, > >> > >> How to support a use case that wants both of shared library > >> and static library with your suggested approach? Do you > >> build Apache Arrow C++ twice for shared library and static > >> library? > >> > >> If so, what CMake package name is used for them? > >> "ArrowShared" and "ArrowStatic"? > >> > >> > >> Thanks, > >> -- > >> kou > >> > >> In <cahgae5er0+vbomjv7w8_dt068yhabclqdkkigo_qp8lz4vr...@mail.gmail.com> > >> "RE: Re: [C++] Static/Shared Linkage in CMakeLists.txt" on Tue, 3 Jun > >> 2025 14:49:02 +0800, > >> Eddie Chang <kalcifer7...@gmail.com> wrote: > >> > >> > Just to clarify, my suggestion was assuming that each build only > produces > >> > either static or shared libraries, not both. > >> > > >> > Given that assumption, wouldn't it be better to define targets using a > >> > single name (without `_static` or `_shared` suffix), and decide in one > >> > place whether that target is defined as STATIC or SHARED depending on > the > >> > `ARROW_BUILD_SHARED`? > >> > > >> > That way, we wouldn't need to switch on `ARROW_BUILD_SHARED` > repeatedly > >> to > >> > determine which target name to link. > >> > > >> > On 2025/06/03 06:05:45 Sutou Kouhei wrote: > >> >> Hi, > >> >> > >> >> Do you want a CMake target that can be used for shared > >> >> linking and static linking? For example, you want to use > >> >> Parquet::parquet for shared linking and static linking, > >> >> right? > >> >> > >> >> In my understanding, we can't do it with CMake. We need to > >> >> specify "SHARED" or "STATIC" when create a CMake target by > >> >> add_library(). > >> >> See also: > >> >> https://cmake.org/cmake/help/latest/command/add_library.html#normal > >> >> > >> >> Thanks, > >> >> -- > >> >> kou > >> >> > >> >> In <ca...@mail.gmail.com> > >> >> "[C++] Static/Shared Linkage in CMakeLists.txt" on Tue, 3 Jun 2025 > >> > 13:45:36 +0800, > >> >> Eddie Chang <ka...@gmail.com> wrote: > >> >> > >> >> > Hello everyone, I've noticed that in our CMakeLists.txt files, we > have > >> >> > multiple instances where we conditionally select either the static > or > >> >> > shared version of a linked target based on a cache variable such as > >> >> > ARROW_BUILD_SHARED. For example, the following pattern appears in > >> > several > >> >> > places: > >> >> > > >> >> > if(ARROW_BUILD_SHARED) > >> >> > set(PARQUET_EXAMPLE_LINK_LIBS parquet_shared) > >> >> > else() > >> >> > set(PARQUET_EXAMPLE_LINK_LIBS parquet_static) > >> >> > endif() > >> >> > > >> >> > I’m wondering if there is a specific reason we don’t set the > >> > static/shared > >> >> > property of the libraries in a single location, and instead > continue > >> >> > duplicating this kind of logic throughout the codebase? > >> >> > >> >
